Coaxial Illumination

Optical Illumination Technique - Coaxial Lighting

Viewing highly-reflective objects with flat surfaces, such as ICs and cross-sectioned samples, is typically difficult to accomplish using ring illumination. When light hits the surface, most of it will reflect away from the lens and result in a dark image. Instead, coaxial (brightfield) illumination is used to view these targets and produce a bright image. Generally, this type of lighting makes use of a half-mirror to match the optical axes of the illumination and lens.